Theory of SERS enhancement: General discussion
Autor: | Alex Keeler, Nicolò Bontempi, Rohit Chikkaraddy, Sumeet Mahajan, Agata Królikowska, Paul Dawson, Leonora Velleman, Volker Deckert, Mike Hardy, Heike Arnolds, Jean-Francois Masson, Marc D. Porter, Ben Hourahine, Fabrizio Giorgis, Natalia Martín Sabanés, Steven E. J. Bell, Giuliana Di Martino, Juan C. Otero, John R. Lombardi, Duncan Graham, Cristiano Matricardi, William Lum, Sebastian Schlücker, Pieter Wuytens, Christian Kuttner, Bart de Nijs, Javier Aizpurua, Richard P. Van Duyne, Marlous Kamp, Jeremy J. Baumberg, George C. Schatz, Stephanie Reich, Dong-Ho Kim, Yikai Xu, Augustus W. Fountain, Ines Delfino, Sylwester Gawinkowski, Ian Bruzas, Roy Goodacre, Alessandro Silvestri, Michael J. Natan, Claudia Fasolato |
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Jazyk: | angličtina |
Rok vydání: | 2017 |
Předmět: |
Materials science
010401 analytical chemistry ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION Halide Charge (physics) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Metal symbols.namesake Chemical physics Molecular vibration visual_art visual_art.visual_art_medium symbols Molecule Settore CHIM/01 - Chimica Analitica sense organs Physics::Chemical Physics Physical and Theoretical Chemistry skin and connective tissue diseases 0210 nano-technology Raman spectroscopy |
Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
Popis: | The first page of this article is displayed as the abstract. Rohit Chikkaraddy opened the discussion of the Introductory Lecture: Regarding quantifying the chemical enhancement, you showed a systematic change in the SERS enhancement for halide substituted molecules due to charge transfer from the metal. Is the extra enhancement due to an inherent increase in the Raman cross-section of the molecule? How do you go about referencing, as the charge transfer changes the vibrational frequency? Richard Van Duyne answered: The extra enhancement is not due to an increase in the Raman cross section, as that is ratioed out in the calculation of the enhancement factor. The charge transfer (CT) process does not transfer a complete electron, it is a fractional degree of CT. Thus the change in vibrational frequency is small. DFT calculations that provide eigenvectors allow one to reference the vibrational modes of the free molecule with those of the adsorbed molecule. Sylwester Gawinkowski asked: You have shown that the enhancement factor curve is redshifted relative to the plasmon resonance band and has a maximum at about 800 nm. This means that the SERS signal should be strongest for excitations in the near infrared spectral region. Why do most SERS reports, particularly related to single molecule SERS, have the excitation in the green or red spectral range and not in the near infrared? |
Databáze: | OpenAIRE |
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